Investigations into cancer biology and therapy are best carried out in the in vivo setting in animal models of the disease. The ability to reach meaningful conclusions from animal studies, such as accurately predicting biological tumor behavior or clinical efficacy of an investigational agent, is greatly enhanced when uniform, readily reproducible animal models are used. In this context, The University of Texas M. D. Anderson Cancer Center (UTMDACC) SPORE in SPORE in Brain Cancer will rely on the Animal Core facility, which was developed over 5 years ago by the Co-Directors, and whose goal is to provide consistent and reproducible heterotopic and orthotopic animal models of brain tumors. The majority of projects in this SPORE grant rely on intracranial (orthotopic) implantation of established, adherent gliomas cell lines, which are molecularly well characterized. However, we have also developed orthotopic xenografts of human brain cancer stem cells, which recent work has indicated are important for the genesis of most solid tumors, including high-grade gliomas. Finally, the Core has obtained and maintains EGFR+ glioma xenografts (gift of C. David James, Ph.D.), which require serial transplant from animal to animal in order to preserve the EGFR+ status of these tumors. Therefore, the Specific Aims of the Animal Core are: Aim 1: Provide support for animal experiments using heterotopic and orthotopic models derived from commercially available human glioma cell lines. Aim 2: Provide support for the animal experiments using orthotopic models derived from brain cancer stem cells. Aim 3: Maintain EGFR+ tumors by serial transplant, exclusively in animals, and provide support for animal experiments using these EGFR+ tumor xenografts. Aim 4: Maintain reference and working stock banks of all cell lines.